DRUCK PRESS????

For any of you 911SC /3.0L owners. I would appreciate any feedback on what the mentioned pressure gauge reads at different RPMs. For example 5th gear 3000rpm etc. etc. Mine reads approx. 2.0 . Being a new owner I would like to get an idea of what it normal???

Sounds a little low ! Top gear at 3000 RPM should hold 4-5 bar. Should be around 2 bar at idle although pressure drops slightly when the oil is hot due to the lower viscosity.

I'd have it checked out.

911 SC:

You should be aware that in Europe the measurement for pressure is "Bar", which is a measure of multiples of air pressure.

Therefore, 1 Bar is 15 psi, plus or minus; 2 Bar is 30 psi, plus or minus, etc. etc.

So if your guage is reading 2 Bar, then you are getting only 30 psi of oil pressure to your engine; this is too low at normal operating temperature and RPM. I would have this checked - either your guage is malfunctioning or your oil pump is....Andras

The rule of thumb is 10psi/1000rpm. Volume is more important than pressure in these systems. If 2.0 bar is 30psi and you're running 3000rpm with the engine hot then there is no cause for immediate alarm. I have always used this "rule" as a minimum for acceptable pressure. How is your pressure at idle? This will tell you something as well.

911SC:

I have an '83 Targa. With a warm engine and at idle I get about 1 bar of pressure. In 5th gear at highway speed (~80 mph) I get right around 4 bar. I go with Brian's suggested 1 bar: 1k rpm rule. Is the pressure better at higher rpm's? Depending on the heat where you are, you might try a greater weight oil (I run 20W50).

Hi'I own a 78SC Euro spec,i rebuilt the engine last year(100,000m).There was no vissible wear in the mains/big ends,oil pressure was about 1 Bar at idle.After the rebuild oil pressure is 4 dropping to 3 Bar at idle.I was told by a Porsche race mechanic SC engines can run with very low oil pressures,and the bottom end of the engines are almost indistructable,i wouldn't worry to much.I rebuilt my engine due to snapped head studs,a common problem on SCs.

Appreciate the feedback. Here is some more data. At idle (800-1000rpm) the pressure gauge reads approx. 1 Bar. At 2000 rpm it reads approx. 2bar, and continues to read at around 2bar even at 3000rpm. Sometimes it is a little higher approx. 3bar . It is a '81 SC with a 3.0 . Engine rebuilt 25K ago. No smoke or significant oil consumption. Engine runs strong.

911SC:

Now that wew seem to have all the facts, it seems to me that you are expereincing no problems with your oil pressure. All of this sounds as things are normal.

I would recommend that you continue to enjoy your car; it's wonderful to drive. Try not to worry about the oil pressure, unless things change radically.....Andras

Once again thanks for the feedback (Andras)....this site is a great source of info.

I have a 82' with 200,000 miles. Light amount of smoke at start an thats it. 5th gear at 3K rpm pressure reads 3.2 bar and at time will read 4 in lower gears.

Hello 911 Sc! The oil pressure readings that you have are identical to the readings that I had on my 1980 911 SC. Once I replaced my "oil pressure sending unit", my readings got alot better but not perfect, and the part wasn't even expensive. The result after I replaced the oil pressure sending unit was that Highway speeds of 60 mph 5th gear 4500 rpms was 3bar although it was alot better than before (used to read 2 or 2.5 bar). Another problem was the transmission to body ground strap. After that was replaced the readings on my car became perfectly normal. Example hot idle 1000 rpms 1.3 bar, highway 60 mph 45 rpms read 4.3 app. I really hope this helps you with your car. I think its natural that when you get a new car and you are testing everything that when you find something that's not perfect you expect it to be an expensive problem. You'll find that Porsche has a reputation for reliability and remember that when attempting to diagnose your problems because even your trusted Porsche mechanic wants to make money.

Kevin:

Just checking on a point that you made in your post. I often travel between track events at 80 MPH (with a radar detector, of course), and my 1983 911SC is turning only 3200 RPM.

Might you have slightly different final gearing than mine? I have owned the car since pick up at the factory, so I know it is "stock". Perhaps there are differences in the final gears between years?....Andras

Andras, sorry about the inaccurate numbers these were numbers that came to mind seeing that I have not been driving the car since last summer. But, I don't remember my RPM's being as low as yours at 80mph.

Kevin,

Thanks for your comments. I will definitely keep them in mind. It's appreciated.

911SC